Heather Heyer died in August when a car slammed into protesters in Charlottesville, Virginia.

14

Last year's deaths by domestic extremists also includes nine by Islamic extremists and five by what the league described as black nationalists.

The vehicular attack on a New York bike path that left eight people dead was considered the single deadliest Islamic extremist attack last year.

"The deadliest extremist-related incident in 2017 involved a vehicle. Given the murder of Heather Heyer also involved a vehicle, the most highly publicized Islamic extremist and white supremacist-related murders in 2017 each used vehicles as weapons -- a first for the United States," the league said.

The ninth death as a result of a suspected Islamist extremist attack was the February killing of a transit security guard in Denver, allegedly by a man who had converted to Islam, according to the report.

Police secure an area in Lower Manhattan in October after a deadly vehicle attack on a bike path.

71

Most of those killed in 2016 extremist attacks were in Orlando.

At least 71 people died in extremist-related killings in 2016, according to the league. The majority of those were from the Orlando nightclub shooting that left 49 people dead and was blamed on an Islamic extremist.